Abstract: This study systematically investigated the responses of morphological, biomass, and physiological parameters in seedlings of the critically endangered species Primulina rubella to six nitrogen concentrations (0, 1.0, 3.0, 7.0, 12.0, and 16.0 mmol·L–1). The results demonstrated that elevated nitrogen levels significantly influenced seedling development, with key growth parameters (plant height, canopy width, leaf area), total biomass, chlorophyll content (18.74%–130.63% increase), soluble protein content, and superoxide dismutase activity (up to 702.98% enhancement) all peaking at 12.0 mmol·L–1 before declining significantly at 16.0 mmol·L–1. Soluble sugar content exhibited an initial decrease followed by stabilization, while proline content showed a distinct decrease (maximum reduction of 64.67% at 12.0 mmol·L–1) before subsequent increase. Comprehensive evaluation identified 12.0 mmol·L–1 as the optimal nitrogen concentration, promoting both optimal growth performance and maximal antioxidant capacity, thereby providing a scientific basis for precision nutrient management in ex situ conservation efforts.

Key words: critically endangered plant, Primulina rubella, nitrogen levels, seedling growth, physiological characteristics

摘要： 通过设置6种氮素浓度(0、1.0、3.0、7.0、12.0和16.0 mmol·L–1)系统分析极危植物红花报春苣苔Primulina rubella幼苗的形态、生物量和生理指标对氮素的响应。结果表明，氮素浓度升高显著影响幼苗生长发育，其中株高、冠幅、叶面积等形态指标及总生物量、叶绿素含量(增幅18.74%～130.63%)、可溶性蛋白含量和超氧化物歧化酶活性(最高提升702.98%)均在12.0 mmol·L–1时达到峰值，而在16.0 mmol·L–1时显著降低；可溶性糖含量呈先降后稳趋势，脯氨酸含量则先降(12.0 mmol·L–1时降幅达64.67%)后升。综合各项指标，12.0 mmol·L–1为适宜氮素施用水平，该浓度下幼苗生长状况最佳且抗氧化能力最强。

关键词: 极危植物, 红花报春苣苔, 氮素水平, 幼苗生长, 生理特性